1. Field of the Invention
The present invention relates to an apparatus for adjusting angle of the back of a seat for a vehicle, and more particularly to an apparatus for adjusting angle of the back of a seat for a vehicle by which the angle can be adjusted accurately without any malfunction when the angle of the back is adjusted to provide comfort for a driver or a passenger, and which the twist caused by the external impact is prevented in driving a vehicle to mitigate the risk of the safety accident to the minimum.
2. Description of the Prior Art
Generally, a seat for a vehicle comprises a front seat, which is constituted by a driver's seat and a front passenger's seat, and a rear seat on which passengers are seated. The front seat is provided such that the driver or the passenger is seated comfortably on the seat, and that the distance in front and rear of the seat and the angle of the back is adjusted freely on the basis of a figure of the driver, whereby the driver can drive the vehicle safely in the most comfortable posture and the passenger can be seated on the passenger's seat in the most comfortable posture.
Such a seat for a vehicle is provided with an apparatus for adjusting the angle of the back of a seat. FIG. 1 shows an apparatus for adjusting the angle of the prior art. As shown in FIG. 1, a turning bracket 31 is mounted on a fixed bracket 11 connected to both sides of the rear of a seat 10 respectively, the turning bracket 31 is connected to a back 30, and mounted on the fixed bracket 11 such that the turning bracket 31 is turned on a hinge 20. On the outer surfaces of the turning bracket is mounted a ratchet 32 having a gear 33 formed thereon. A gear 42 is formed on the upper surface of a actuating piece 40, which is arranged beneath the ratchet and turned by means of the fixed bracket 11 and a hinge 41. The gear 42 is engaged with the gear 33. A actuating lever 50 is provided for adjusting a position of the actuating piece. The actuating lever 50 has one end connected by means of the hinge. The actuating lever 50 includes a guiding hole 51 which is formed at the middle thereof and which a guide pin 43 formed at the end of the actuating piece is inserted in. To a fixing rail 60 for fixing the lower part of the one end of the actuating lever and the seat is connected a elastic spring 70 for lowering the actuating lever by virtue of its own elasticity.
With the apparatus for adjusting the angle of the back of prior art as described above, the actuating lever remains lowered by virtue of the elasticity of the elastic spring, as shown in FIG. 1a, so that the guide pin inserted in the guiding hole is positioned at the upper end of the guiding hole, and the end of the actuating piece is lowered on the hinge. As a result, the gear of the actuating piece and the gear of the ratchet remain engaged with each other, thus the back is locked.
To adjust the angle of the back in the above mentioned conditions, as shown in FIG. 1b, the end of the actuating lever is pulled upward so that the actuating lever is turned on the hinge. Consequently, the guide pin inserted in the guiding hole is positioned at the lower end of the guiding hole, and the actuating piece is lowered on the hinge. As a result, the gears engaged are separated from each other.
After the angle of the back is adjusted for the comfort of the users, released is the actuating lever which is pulled. Then, the actuating lever is lowered on the hinge by virtue of the elasticity of the elastic spring. The guide pin is positioned at the upper end of the guiding hole and the end of the actuating piece rises on the hinge, as shown in FIG. 1b, by the turned angle of the guiding hole. Consequently, the gears are engaged with each other to lock the back at the adjusted angle.
However, the apparatus for adjusting the angle of the back of the prior art as described above adjusts the angle of the back and therefore locks the back at the adjusted angle, however, in that the actuating lever is actuated by virtue of the elasticity to turn the actuating piece, thus the gears formed on the actuating piece and the ratchet are engaged with each other or separated from each other. Consequently, if the external impact, such as shock from the collision of the vehicle in driving the vehicle, the actuating lever may be turned. As a result, the actuating piece is turned on the hinge by the turned angle of the actuating lever, therefore the gears engaged may be separated from each other. In this case, the upper part of the body of the driver is moved forward by the turning of the back forward. Accordingly, the upper part of the body is dashed against the steering wheel to lose his life from the safety accident.